title: An unusual outbreak of rotavirus genotype G2P[6] during the 2005-2006 epidemic season in Philadelphia.
abstract: Most rotavirus gastroenteritis is caused by G1P[8] strains. When G2 infections are encountered, the P type has most often been reported to be P[4]. The purpose of our study was to describe an unusual outbreak of G2P[6] cases. Children presenting to The Children's Hospital of Philadelphia with acute gastroenteritis have been monitored for rotavirus antigen in stool by ELISA (with G-typing if ELISA positive) since 1994-1995. Compared to the last 12 rotavirus seasons before the 2006 introduction of a new rotavirus vaccine, the 2005-2006 season had by far the highest number of evaluable rotavirus infections [n = 275 from September 2005 through June 2006, of which 261 (95%) were G typed] and the greatest number of G2 cases (n = 101, 39% of typed strains). Only 16% of G2 strains were associated with P[4], whereas genotype G2P[6] was responsible for 83% of the G2 infections. Eighty-eight percent of the 84 G2P[6] cases occurred in the 60% of patients who were African-Americans, most of whom were urban residents. Among 157 African-American patients, G2 cases (n = 80; 52%) predominated, including 74 due to G2P[6]. Children <6 months old accounted for 27% of cases overall, but 36% of the G2P[6] cases. G2 rotaviruses caused over a third of the community-acquired rotavirus cases in children presenting to CHOP in 2005-2006, attesting to the potential impact of G2 strains during some epidemics. The large majority of G2 strains had the rare P[6] genotype. Urban African-American children under 6 months of age were disproportionately affected.
authors.affiliation: The Children's Hospital of Philadelphia, Philadelphia, PA, USA. clarkf@email.chop.edu
authors.forename: H Fred
authors.initials: HF
authors.lastname: Clark
authors.forename: Diane
authors.initials: D
authors.lastname: Lawley
authors.forename: Daniel
authors.initials: D
authors.lastname: DiStefano
authors.forename: Marianne
authors.initials: M
authors.lastname: Maliga
authors.forename: Bronwyn
authors.initials: B
authors.lastname: Kilby
authors.forename: Greg
authors.initials: G
authors.lastname: Kulnis
authors.forename: Laura
authors.initials: L
authors.lastname: Mallette
authors.forename: Mark J
authors.initials: MJ
authors.lastname: DiNubile
mesh_terms: D000956:Antigens, Viral / Q000032:analysis; D002675:Child, Preschool; D004196:Disease Outbreaks; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000821:virology; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D017720:Molecular Epidemiology; D058889:Molecular Typing; D015143:Philadelphia / Q000453:epidemiology; D012401:Rotavirus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D012400:Rotavirus Infections / Q000453:epidemiology* / Q000821:virology
chemical_list: D000956:Antigens, Viral